Saute sliced onion in 1 Tablespoon oil in a large skillet. Remove onion, and set aside.
Combine flour and salt in a shallow dish or pan; dredge steaks in the flour mixture making sure they are covered on both sides. Heat 1/4 cup oil in the skillet and add the coated steaks. Cover and cook over medium heat for 4 minutes on each side or until done. Remove steaks and keep warm. Add the onion, mushrooms, and sour cream to the pan droppings in the skillet; cook until thoroughly heated (do not boil).
Combine water and salt in a pan; bring to a rapid boil. Add noodles, and boil for 7 to 9 minutes, stirring occasionally; drain. Combine noodles, butter and parsley.
Plate the noodles on a serving dish or on 4 individual dinner dishes. Arrange steaks on top of noodles and spoon sauce over the top of the steak.